I notice some cyclists take the A71 in to livi at lizzie brice in Livingston but this seems more dangerous that first part of A899.
On the A71 in Livingston its 2 narrow for a car to pass safely with oncoming traffic. On the A899 there is 2 lanes so cars can pass, even when 2 cars pass at once more room than on the A71 when a car passes and an oncoming car.
I always think the most dangerous part of a trip from Livingston to Edinburgh is the A71 is between Wilkieston and the turn of to Curriehill road as cars cannot overtake and corners so cars come up fast behind and have to brake.
Many people drive too fast to stop on narrow roads with corners. I think roads like the A71 from Wilkieston to curriehill turn off amongst the most dangers road to cycle on.
I am not sure that the first stage of the A899 when entering Livingston is that dangerous as cars have good visibility a passing lane and cars enter exit the roundabout from a slower speed.
When leaving Livingston entering the A899 it is more a conflict problem than a safety one, cars enter the slip road slowing at round about there then stuck behind until the slip roads splits to 2.
it causes a nuisance to traffic stuck behind having to wait but as low speed and good visibility and can spot someone from a slow speed not that great a safety issue https://www.google.co.uk/maps/@55.8857263,-3.5027863,3a,75y,63.32h,68t/data=!3m6!1e1!3m4!1sORJxJIB3sOOWyqBK5iy6sA!2e0!7i13312!8i6656 unlike say narrow sections of the A71 where traffic
may not stop and hit you at high speed https://www.google.co.uk/maps/@55.9061976,-3.3780754,3a,75y,253.87h,70.56t/data=!3m6!1e1!3m4!1ssxNW7CpP0P4P6a9Szwcx1g!2e0!7i13312!8i6656 .